[Federal Register Volume 84, Number 119 (Thursday, June 20, 2019)]
[Proposed Rules]
[Pages 28776-28784]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-12948]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2019-0180; FRL-9995-10-Region 8]


Approval and Promulgation of Air Quality State Implementation 
Plans; Utah; Interstate Transport Requirements for Nitrogen Dioxide, 
Sulfur Dioxide, and Fine Particulate Matter

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve State Implementation Plan (SIP) submissions from the State of 
Utah regarding certain interstate transport requirements of the Clean 
Air Act (CAA or ``Act''). These submissions respond to the EPA's 
promulgation of the 2010 nitrogen dioxide (NO2) national 
ambient air quality standards (NAAQS), the 2010 sulfur dioxide 
(SO2) NAAQS, and the 2012 fine particulate matter 
(PM2.5) NAAQS. The submissions address the requirement that 
each SIP contain adequate provisions prohibiting air emissions that 
will significantly contribute to nonattainment or interfere with 
maintenance of these NAAQS in any other state.

DATES: Written comments must be received on or before July 22, 2019.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2019-0180, to the Federal Rulemaking Portal: https://www.regulations.gov. Follow the online instructions for submitting 
comments. Once submitted, comments cannot be edited or removed from 
www.regulations.gov. The EPA may publish any comment received to its 
public docket. Do not submit electronically any information you 
consider to be Confidential Business Information (CBI) or other 
information whose disclosure is restricted by statute. Multimedia 
submissions (audio, video, etc.) must be accompanied by a written 
comment. The written comment is considered the official comment and 
should include discussion of all points you wish to make. The EPA will 
generally not consider comments or comment contents located outside of 
the primary submission (i.e., on the web, cloud, or other file sharing 
system). For additional submission methods, the full EPA public comment 
policy, information about CBI or multimedia submissions, and general 
guidance on making effective comments, please visit http://www2.epa.gov/dockets/commenting-epa-dockets.
    Docket: All documents in the docket are listed in the 
www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in www.regulations.gov or in hard copy at the Air and Radiation 
Division, Environmental Protection Agency (EPA), Region 8, 1595 Wynkoop 
Street, Denver, Colorado 80202-1129. The EPA requests that if at all 
possible, you contact the individual listed in the FOR FURTHER 
INFORMATION CONTACT section to view the hard copy of the docket. You 
may view the hard copy of the docket Monday through Friday, 8:00 a.m. 
to 4:00 p.m., excluding federal holidays.

FOR FURTHER INFORMATION CONTACT: Adam Clark, Air Quality Planning 
Branch, EPA, Region 8, Mailcode 8ARD-QP, 1595 Wynkoop Street, Denver, 
Colorado 80202-1129, (303) 312-7104, clark.adam@epa.gov.

SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,'' 
``us'' or ``our'' is used, we mean the EPA.

Table of Contents

I. Background
    A. Interstate Transport
    B. Utah's Submissions
II. Interstate Transport Evaluation
    A. Evaluation for the 2010 1-Hour NO2 NAAQS
    1. EPA's General Approach to Evaluating the 2010 NO2 
NAAQS
    2. State's Submission
    3. EPA's Analysis
    B. Evaluation for the 2010 1-Hour SO2 NAAQS
    1. EPA's General Approach to Evaluating the 2010 SO2 
NAAQS
    2. State's Submission
    3. EPA's Analysis
    C. Evaluation for the 2012 Annual PM2.5 NAAQS
    1. EPA's General Approach to Evaluating the 2012 
PM2.5 NAAQS
    2. State's Submission
    3. EPA's Analysis
III. Proposed Action
IV. Statutory and Executive Order Reviews

I. Background

    Section 110(a)(1) of the CAA requires states to submit SIPs meeting 
the applicable requirements of section 110(a)(2) within 3 years after 
promulgation of a new or revised NAAQS or within such shorter period as 
the EPA may prescribe. Section 110(a)(2) requires states to address

[[Page 28777]]

structural SIP elements such as requirements for monitoring, basic 
program requirements, and legal authority that are designed to provide 
for implementation, maintenance, and enforcement of the NAAQS. The EPA 
refers to the SIP submissions required by these provisions as 
``infrastructure SIPs.'' Section 110(a) imposes the obligation upon 
states to make an infrastructure SIP submission to the EPA for a new or 
revised NAAQS, but the contents of individual state submissions may 
vary depending upon the facts and circumstances. This proposed rule 
pertains to the infrastructure SIP requirements for interstate 
transport of air pollution.

A. Interstate Transport

    Section 110(a)(2)(D)(i) of the CAA requires SIPs to include 
provisions prohibiting any source or other type of emissions activity 
in one state from emitting any air pollutant in amounts that will 
contribute significantly to nonattainment, or interfere with 
maintenance, of the NAAQS, or interfere with measures required to 
prevent significant deterioration of air quality or to protect 
visibility in any other state. This proposed rule addresses the two 
requirements under section 110(a)(2)(D)(i)(I), which we refer to as 
prong 1 (significant contribution to nonattainment of the NAAQS in any 
other state) and prong 2 (interference with maintenance of the NAAQS in 
any other state).\1\ The EPA often refers to SIP revisions addressing 
the requirements of section 110(a)(2)(D)(i)(I) as ``interstate 
transport SIPs.''
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    \1\ The remaining interstate transport requirements of CAA 
section 110(a)(2)(D)(i) for the 2010 NO2, 2010 
SO2 and 2012 PM2.5 NAAQS for Utah have been 
addressed in prior State submissions and EPA rulemakings. 81 FR 
71991 (October 19, 2016); 81 FR 50626 (August 2, 2016). 
Specifically, this includes the section 110(a)(2)(D)(i)(II) 
requirements relating to interference with measures required to be 
included in the applicable implementation plan for any other state 
under part C to prevent significant deterioration of air quality 
(prong 3) or to protect visibility (prong 4).
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    The EPA evaluates each state's interstate transport SIP to see how 
the state evaluates the transport of air pollution to other states for 
a given air pollutant; what types of information the state used in its 
analysis; how that analysis compares with prior EPA rulemakings, 
modeling, monitoring, and guidance; and what conclusions were drawn by 
the state. If the EPA concludes that the SIP contains adequate 
provisions to prohibit sources from emitting air pollutants that 
significantly contribute to nonattainment, or interfere with 
maintenance, of a given NAAQS in any other state, we will approve the 
state's submission with regard to prongs 1 and 2 of CAA section 
110(a)(2)(D)(i)(I).
    Each of the following NAAQS revisions triggered the requirement for 
states to submit infrastructure SIPs, including provisions to address 
interstate transport prongs 1 and 2. On January 22, 2010, the EPA 
promulgated a new 1-hour primary NAAQS for NO2 at a level of 
100 parts per billion (ppb) while retaining the annual standard of 53 
ppb.\2\ On June 2, 2010, the EPA promulgated a new primary 1-hour 
SO2 standard of 75 ppb and retained the secondary 3-hour 
standard of 0.5 parts per million (ppm).\3\ Finally, on December 14, 
2012, the EPA revised the primary annual PM2.5 standard by 
lowering the level to 12.0 micrograms per cubic meter ([mu]g/m\3\) and 
retained the secondary annual PM2.5 standard of 15.0 
[micro]g/m\3\ and the primary and secondary 24-hour PM2.5 
standards of 35 [mu]g/m\3\.\4\
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    \2\ 75 FR 6474 (February 9, 2010).
    \3\ 75 FR 35520 (June 22, 2010).
    \4\ 78 FR 3086 (January 15, 2013).
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    As discussed further in this notice, the EPA proposes to determine 
that Utah's SIP contains adequate provisions to prohibit sources from 
emitting air pollutants in amounts that significantly contribute to 
nonattainment or interfere with maintenance of the 2010 NO2, 
2010 SO2 and 2012 PM2.5 NAAQS.

B. Utah's Submissions

    The State of Utah submitted infrastructure SIPs for the 2010 
NO2 NAAQS on January 31, 2013, and for the 2010 
SO2 NAAQS on June 2, 2013. In both of these submissions, the 
State addressed interstate transport prongs 1 and 2 by referencing the 
EPA's November 19, 2012 Memorandum \5\ which outlined the EPA's 
intention to abide by the August 21, 2012 decision of the U.S. Court of 
Appeals for the D.C. Circuit, holding that a SIP cannot be deemed 
deficient for failing to meet the prong 1 and 2 requirements in Section 
110(a)(2)(D)(i) before the EPA quantifies the state's obligation. EME 
Homer City Generation, L.P. v. EPA, 696 F.3d 7 (D.C. Cir. 2012). Utah 
stated that the EPA had not yet quantified Utah's interstate transport 
obligation under the 2010 NO2 or 2010 SO2 NAAQS 
and therefore Utah's infrastructure SIPs were adequate for section 
110(a)(2)(D)(i)(I).\6\
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    \5\ See ``Next Steps for Pending Redesignation Requests and 
State Implementation Plan Actions Affected by the Recent Court 
Decision Vacating the 2011 Cross-State Air Pollution Rule,'' signed 
by EPA Assistant Administrator Gina McCarthy November 19, 2012. This 
memorandum is in the docket for this action.
    \6\ These submissions are available in the docket for this 
action.
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    On April 29, 2014, the U.S. Supreme Court reversed and remanded the 
D.C. Circuit's EME Homer City ruling and upheld the EPA's approach in 
the Cross-State Air Pollution Rule. EPA v. EME Homer City Generation, 
L.P., 572 U.S. 489 (2014). As a result of the Supreme Court reversal, 
each state was again required to address the interstate transport 
requirements of 110(a)(2)(D)(i) regardless of whether the EPA had 
quantified the state's obligation. In accordance with the Supreme 
Court's decision, on May 8, 2018 Utah submitted to the EPA 2010 
NO2 and 2010 SO2 infrastructure SIPs, both of 
which contained new analyses addressing interstate transport prongs 1 
and 2 of Section 110(a)(2)(D)(i) for the respective NAAQS. These 
submissions supplement the State's prior 2013 interstate transport SIP 
submissions for both NAAQS. Utah submitted an infrastructure SIP for 
the 2012 PM2.5 NAAQS, including an interstate transport SIP, 
on December 22, 2015. The EPA will discuss these submissions in further 
detail later in this proposed action.

II. Interstate Transport Evaluation

A. Evaluation for the 2010 1-Hour NO2 NAAQS

1. EPA's General Approach To Evaluating the 2010 NO2 NAAQS
    Unlike certain other NAAQS like ozone and PM2.5, the EPA 
has not developed a recommended approach for states to use when 
addressing prongs 1 and 2 for the 2010 NO2 NAAQS. Following 
promulgation of the 2010 NO2 NAAQS, the EPA designated all 
areas of the United States as ``unclassifiable/attainment'' for this 
NAAQS because monitors throughout the country had indicated no 
violations of the NAAQS from 2008-2010.\7\ 77 FR 9532, February 17, 
2012. Additionally, no violations occurred at any monitor in the 
country in the most recent available design value period of 2015-
2017.\8\ For these reasons, 110(a)(2)(D)(i)(I) demonstrations for 
states have been relatively straightforward because the EPA has not 
identified areas in any state to which emissions from another state 
would likely contribute significantly to nonattainment or interfere 
with maintenance.
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    \7\ For comparison with the 2010 NO2 1-hour NAAQS, a 
three-year design value is used. 40 CFR 50.11(f).
    \8\ See https://www.epa.gov/air-trends/air-quality-design-values#report. As this report indicates, no regulatory monitor in 
the U.S. recorded a design value above 78 ppb for the 2015-2017 
design value period.

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[[Page 28778]]

2. State's Submission
    Utah conducted a weight of evidence analysis to examine whether 
NO2 emissions from Utah adversely affect attainment or 
maintenance of the 2010 NO2 NAAQS in downwind states. In 
this analysis, the State reviewed ambient monitoring data in Utah and 
neighboring states, which all indicated that no monitor values in Utah 
or neighboring states approach the level of the 2010 NO2 
NAAQS. Based on this monitoring data, Utah concluded that the emissions 
from the State will not contribute significantly to nonattainment or 
interfere with maintenance of the 2010 NO2 NAAQS in any 
other state, and therefore the SIP meets the requirements of section 
110(a)(2)(D)(i)(I) prongs 1 and 2 for this NAAQS.
3. EPA's Analysis
    In addition to the information provided in the SIP, the EPA notes 
that the highest monitored valid NO2 design values in each 
state bordering Utah are well below the NAAQS (see Table 1, below), as 
are the maximum single year 98th percentile values from each 
neighboring state between 2015-2017 (see Table 2, below). These facts 
further support the State's assertion that significant contribution to 
nonattainment or interference with maintenance of the NO2 
NAAQS from Utah is very unlikely. With respect to prong 2 (interference 
with maintenance), specifically, in addition to the lack of areas 
violating the NO2 NAAQS, there are also no areas in 
neighboring states approaching a violation of the 2010 NO2 
NAAQS (i.e., 100 ppb) which might therefore be expected to have 
difficulty maintaining the standard. With respect to both prongs, we 
also note that there are no areas elsewhere in the United States 
approaching a violation of the 2010 NO2 NAAQS.\9\
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    \9\ Id.

    Table 1--1-Hour NO2 Design Values in Utah and Neighboring States
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                                                          2015-2017 1-hr
                          State                             NO2 design
                                                            value (ppb)
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Utah....................................................              42
Arizona.................................................              60
Colorado................................................              71
Nevada..................................................              55
New Mexico..............................................              45
Wyoming.................................................              40
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 Table 2--Max 98th Percentile NO2 Concentration in Utah and Neighboring
                                 States
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                                                          Highest single
                                                             year 98th
                                                            percentile
                    State                         Year      value from
                                                             2015-2017
                                                               (ppb)
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Utah.........................................       2016              61
Arizona......................................       2017              67
Colorado.....................................       2016              75
Idaho........................................       2017              50
Nevada.......................................       2017              61
New Mexico...................................       2016              46
Wyoming......................................       2017              60
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    Based on all of these factors, the EPA proposes to concur with the 
State's conclusion in its January 31, 2013 and supplemental May 8, 2018 
submissions that emissions from Utah will not contribute significantly 
to nonattainment or interfere with maintenance of the 2010 
NO2 NAAQS in other states. The EPA is therefore proposing to 
approve Utah's January 31, 2013 and supplemental May 8, 2018 
NO2 submissions.

B. Evaluation for the 2010 1-Hour SO2 NAAQS

1. EPA's General Approach To Evaluating the 2010 SO2 NAAQS
    Although SO2 is emitted from a similar universe of point 
and nonpoint sources as is directly emitted PM2.5 and the 
precursors to ozone and PM2.5, interstate transport of 
SO2 is unlike the transport of PM2.5 or ozone 
because SO2 emissions sources usually do not have long range 
SO2 impacts. The transport of SO2 relative to the 
1-hour NAAQS is more analogous to the transport of Pb relative to the 
Pb NAAQS in that emissions of SO2 typically result in 1-hour 
pollutant impacts of possible concern only near the emissions source. 
However, ambient 1-hour concentrations of SO2 do not 
decrease as quickly with distance from the source as do 3-month average 
concentrations of Pb, because SO2 gas is not removed by 
deposition as rapidly as are Pb particles and because SO2 
typically has a higher emissions release height than Pb. Moreover, 
while emitted SO2 has wider ranging impacts than emitted Pb, 
it does not have such wide-ranging impacts that treatment in a manner 
similar to ozone or PM2.5 would be appropriate. The 
approaches that the EPA has adopted for ozone or PM2.5 
transport are too regionally focused and the approach for Pb transport 
is too tightly circumscribed to the source. SO2 transport is 
therefore a unique case and requires a different approach.
    In SO2 transport analyses, we focus on a 50 km-wide zone 
because the physical properties of SO2 result in relatively 
localized pollutant impacts near an emissions source that drop off with 
distance. Given the physical properties of SO2, the EPA 
selected the ``urban scale''--a spatial scale with dimensions from 4 to 
50 kilometers (km) from point sources--as that scale has been an 
appropriate range both for monitoring SO2 concentrations and 
for modeling SO2 impacts from such sources.\10\ As such, the 
EPA utilized an assessment up to 50 km from point sources in order to 
assess trends in area-wide air quality that might impact downwind 
states.
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    \10\ For the definition of spatial scales for SO2, 
please see 40 CFR part 58, Appendix D, section 4.4 (``Sulfur Dioxide 
(SO2) Design Criteria''). For further discussion on how 
the EPA is applying these definitions with respect to interstate 
transport of SO2, see 82 FR 21351, 21352, 21354 (May 8, 
2017) (proposed approval of Connecticut's SO2 transport 
SIP); 82 FR 37013 (Aug. 8, 2017) (final approval).
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2. State's Submission
    Utah conducted a weight of evidence analysis to examine whether 
SO2 emissions from Utah contribute significantly to 
nonattainment or interfere with maintenance of the 2010 SO2 
NAAQS in downwind states. Utah's analysis first reviewed monitoring 
data in neighboring states to determine whether there were cross-state 
areas to which Utah could potentially contribute significantly to 
nonattainment. Utah concluded that the only monitors in neighboring 
states near or above the NAAQS were violating monitors located in the 
Miami, Arizona and Hayden, Arizona SO2 nonattainment 
areas.\11\ Utah then analyzed the SO2 source within the 
State with the closest proximity to the Arizona nonattainment areas. 
The State determined the distance (531 km) between this source (Cci 
Paradox Midstream, Llc: Lisbon Natural Gas Processing Plant) and the 
nearest nonattainment area (Miami, Arizona) showed that Utah will not 
contribute significantly to nonattainment in Arizona. For its analysis 
of interference with maintenance, Utah reviewed the sources with over 
100 ton per year (tpy) SO2 emissions in the State within 50 
km of a state border, the distance from the nearest cross-state 
SO2 monitors to Utah sources, and its proximity to the 
nearest former 2010 SO2 nonattainment area in Billings, 
Montana. Utah also pointed to the significant decrease in 
SO2 emissions from sources in the State over time, and its 
current low levels of monitored SO2, as further evidence 
that Utah will not significantly contribute to

[[Page 28779]]

nonattainment of the 2010 SO2 NAAQS in any other state.
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    \11\ https://www3.epa.gov/airquality/greenbook/tbtc.html.
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3. EPA's Analysis
Prong 1: Significant Contribution to Nonattainment
    The EPA proposes to approve Utah's June 2, 2013 and supplemental 
May 8, 2018 submittals with respect to the interstate transport 
requirements of CAA section 110(a)(2)(D)(i)(I), prong 1 for the 2010 
SO2 NAAQS, as discussed below. We have analyzed the air 
quality, emission sources and emission trends in Utah and neighboring 
states, i.e., Arizona, Colorado, Idaho, New Mexico, Nevada and Wyoming. 
Based on that analysis, we propose to find that Utah will not 
significantly contribute to nonattainment of the 2010 SO2 
NAAQS in any other state.
    We first reviewed 2015-2017 1-hour SO2 design value 
concentrations for Utah and neighboring states.\12\ In Table 3, below, 
we have included monitoring data from four scenarios: (1) All of the 
monitor data from Utah; \13\ (2) the monitor with the highest 
SO2 level in each neighboring state; (3) the monitor in each 
neighboring state located closest to the Utah border; and (4) all 
monitors in each neighboring state within 50 km of the Utah border.\14\ 
For monitors without a valid 2015-2017 design value, we have instead 
elected to present the highest annual 99th percentile daily maximum 1-
hour SO2 concentration between 2015 and 2017. These values 
are shown in the far-right column of Table 3, below. As the table 
indicates, all of these concentrations are below the level of the 2010 
SO2 NAAQS.
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    \12\ Data retrieved from EPA's https://www.epa.gov/air-trends/air-quality-design-values#report.
    \13\ There are currently three SO2 monitors operating 
in Utah. However, two of these (AQS Site IDs 490352005 and 
490353010) began operation in 2018, and therefore do not have data 
sufficient to assist the EPA in this technical analysis. We note 
that the highest 1-hr SO2 concentration from either of 
the monitors in 2018 was 7 ppb, or roughly 9% of the NAAQS.
    \14\ There are no states within 50 km of the Utah border that 
are not also neighboring states.

                           Table 3--SO2 Monitor Values in Utah and Neighboring States
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                                                                                                    Annual 99th
                                                                                                   percentile 1-
                                                                      Approx.        2015-2017      hour daily
           State/area                Scenario         Site ID       distance to    design value     maximum SO2
                                                                    Utah border        (ppb)      Concentration,
                                                                       (km)                       2015-2017 \15\
 
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Arizona/Phoenix.................               3       040139997             388               6
Arizona/Hayden..................               2       040071001             443             295
Colorado/Denver.................               3       080310026             346              15
Colorado/Colorado Springs.......               2       080410015             366              40
Idaho/Pocatello.................               2       160050004             102              38
Idaho/Soda Springs..............               3       160290031              76              30
Nevada/Las Vegas................            2, 3       320030540             134               6
New Mexico/Farmington...........            2, 3       350451005              57            NA *       16 (2017)
Utah/Salt Lake City.............               1       490353006              76            NA *       13 (2016)
Wyoming/Rock Springs............               3       560370300             105              21
Wyoming/Riverton................               2       560130003             315            NA *       65 (2017)
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* The DV for this site is invalid due to incomplete data and/or quality assurance issues for this period and is
  not for use in comparison to the NAAQS.

    The EPA reviewed these data to see whether there were any 
regulatory monitoring sites, particularly near the Utah border, with 
elevated SO2 concentrations that might warrant further 
investigation with respect to interstate transport of SO2 
from emission sources near any given monitor. As shown, at the monitors 
with valid design values, there are no violating design values in Utah 
or neighboring states apart from Arizona, and the nearest monitor with 
the violating design value in Arizona is 443 km from the Utah border.
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    \15\ These values are only presented for monitors without a 
valid 2015-2017 design value.
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    The data presented in Table 3, above, show that Utah's network of 
SO2 monitors, while limited, indicates that monitored 1-hour 
SO2 levels in Utah were 9% of the 75 ppb level of the NAAQS. 
As shown, there are no Utah monitors located within 50 km of a 
neighboring state's border, nor are there any monitors in neighboring 
states located within 50 km of the Utah border. Thus, these air quality 
data do not, by themselves, indicate any particular location that would 
warrant further investigation with respect to SO2 emission 
sources that might significantly contribute to nonattainment in the 
neighboring states. However, because the monitoring network is not 
necessarily designed to find all locations of high SO2 
concentrations, we have also conducted a source-oriented analysis.
    As noted, the EPA finds that it is appropriate to examine the 
impacts of emissions from stationary sources in Utah in distances 
ranging from 0 km to 50 km from the facility. Utah assessed point 
sources up to 50 km from state borders to evaluate SO2 
transport. The list of sources emitting 100 tpy \16\ or more of 
SO2 in 2017 within 50 km from Utah state borders is shown in 
Table 4 below.
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    \16\ Utah limited its analysis to Utah sources of SO2 
emitting at least 100 tpy. We agree with Utah's choice to limit its 
analysis in this way, because in the absence of special factors, for 
example the presence of a nearby larger source or unusual physical 
factors, Utah sources emitting less than 100 tpy can appropriately 
be presumed to not be adversely impacting SO2 
concentrations in downwind states.

[[Page 28780]]



                             Table 4--Utah SO2 Sources Near Neighboring States \17\
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                                                                                                    Neighboring
                                           2017 SO2       Distance to      Approx. distance to     state source
              Utah source                  emissions      Utah border      nearest neighboring       2017 SO2
                                           (tons) *          (km)        state SO2 source  (km)      emissions
                                                                                                      (tons)
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CCI Paradox Midstream LLC: Lisbon           499 (2016)              20  68 (Nucla Generating                 153
 Natural Gas Processing Plant--San                                       Station--Montrose
 Juan County, Utah.                                                      County, Colorado).
Holcim Inc.: Devils Slide Plant--                  196              41  109 (Naughton Power                4,047
 Morgan County, Utah.                                                    Plant--Lincoln County,
                                                                         Wyoming).
----------------------------------------------------------------------------------------------------------------
* Emissions data throughout this document were obtained using EPA's Emissions Inventory System (EIS) Gateway.

    Table 4  also shows the distance from Utah sources located near a 
neighboring state to the nearest out-of-state SO2 source 
emitting above 100 tpy of SO2, because elevated levels of 
SO2, to which SO2 emitted in Utah may have a 
downwind impact, are most likely to be found near such sources. As 
shown, both Utah sources within 50 km of a neighboring state are beyond 
50 km from the nearest major out-of-state source, with the shortest 
distance between such cross-state SO2 sources at 68 km.\18\ 
Given the localized range of potential 1-hour SO2 impacts 
and the distance between sources, Table 4 suggests that emissions from 
these Utah sources are unlikely to contribute significantly to 
nonattainment of the 2010 SO2 NAAQS in neighboring states. 
Additionally, the largest neighboring-state source in Table 4, Naughton 
Power Plant, was modeled and showed attainment with the 2010 
SO2 NAAQS.\19\ Based on this modeling, the EPA designated 
Lincoln County, Wyoming as attainment/unclassifiable for this NAAQS. 
See 83 FR 1170, January 9, 2018. This provides additional support for 
our proposed conclusion that emissions from the Utah sources in Table 4 
do not significantly contribute to nonattainment of the 2010 
SO2 NAAQS in neighboring states.\20\
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    \17\ The EPA did not include information about sources located 
on tribal lands within the outer boundary of the state of Utah, as 
the State is not the regulatory authority for these sources.
    \18\ The EPA notes that the Nucla Generating Station is required 
by the Colorado regional haze SIP to shut down before December 31, 
2022. See 83 FR 31332 (July 5, 2018).
    \19\ See ``Chapter 45: Intended Round 3 Area Designations for 
the 2010 1-Hour SO2 Primary National Ambient Air Quality 
Standard for Wyoming,'' in the docket for this action and in the 
docket for the EPA's Round 3 2010 SO2 Designations at 
EPA-HQ-OAR-2017-0003-0608.
    \20\ While designations may provide useful information for 
purposes of analyzing transport, particularly for a more source-
specific pollutant such as SO2, EPA notes that 
designations themselves are not dispositive of whether or not upwind 
emissions are impacting areas in downwind states. EPA has 
consistently taken the position that as to impacts, CAA section 
110(a)(2)(D) refers only to prevention of `nonattainment' in other 
states, not to prevention of nonattainment in designated 
nonattainment areas or any similar formulation requiring that 
designations for downwind nonattainment areas must first have 
occurred. See e.g., Clean Air Interstate Rule, 70 FR 25162, 25265 
(May 12, 2005); Cross-State Air Pollution Rule, 76 FR 48208, 48211 
(Aug. 8, 2011); Final Response to Petition from New Jersey Regarding 
SO2 Emissions From the Portland Generating Station, 76 FR 
69052 (Nov. 7, 2011) (finding facility in violation of the 
prohibitions of CAA section 110(a)(2)(D)(i)(I) with respect to the 
2010 1-hour SO2 NAAQS prior to issuance of designations 
for that standard).
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    The EPA also reviewed the location of sources in neighboring states 
emitting more than 100 tpy of SO2 and located within 50 km 
of the Utah border (see Table 5) that were not already addressed in 
Table 4. As shown in Table 5, there is only one such source, and the 
shortest distance between it and any Utah source that emits 100 tpy or 
more of SO2 is 233 km. The distance shown in Table 5 
indicates that there are no locations in neighboring states that would 
warrant further investigation with respect to Utah SO2 
emission sources that might contribute significantly to nonattainment 
of the 2010 SO2 NAAQS. The Hayden and Miami, Arizona 2010 
SO2 nonattainment areas, which Utah reviewed as part of its 
analysis, are over 380 km from the nearest Utah border and so were not 
included in Table 5. Utah asserted that the significant distance 
between its border and these nonattainment areas indicates that it is 
highly unlikely that SO2 emissions generated in Utah are 
contributing significantly to either nonattainment area in Arizona, and 
the EPA proposes to agree with this conclusion.

                               Table 5--Neighboring State SO2 Sources Near Utah *
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                                                                                                    Utah source
                                           2016 SO2       Distance to      Approx. distance to         2016
                Source                     emissions      Utah border    nearest Utah SO2 source     emissions
                                            (tons)           (km)                 (km)                (tons)
----------------------------------------------------------------------------------------------------------------
Navajo Generating Station--Navajo                3,585              11  233 (Lisbon Natural Gas              499
 Nation.                                                                 Processing Plant).
----------------------------------------------------------------------------------------------------------------
* We have not included sources that are duplicative of those in Table 3.

    In conclusion, for interstate transport prong 1, we reviewed 
ambient SO2 monitoring data and SO2 emission 
sources both within Utah and in neighboring states. Based on this 
analysis, we propose to determine that emissions from Utah will not 
significantly contribute to nonattainment of the 2010 SO2 
NAAQS in any other state and therefore propose to approve the June 2, 
2013 and supplemental May 8, 2018 SO2 submissions with 
respect to this requirement.
Prong 2: Interference With Maintenance
    The EPA also proposes to approve the June 2, 2013 and supplemental 
May 8, 2018 submissions with respect to the prong 2 requirement. In its 
prong 2 analysis, Utah reviewed ambient SO2 monitoring data, 
emissions trends within Utah, and potential SO2 impacts on 
the Billings, Montana area, which is currently in ``maintenance'' 
status for the 2010 SO2 NAAQS, noting the large distance 
between the nearest Utah border and the Billings area (457 km). 
However, in previous actions the EPA has analyzed prong 2 by evaluating 
the

[[Page 28781]]

potential impact of a state's emissions on areas that are currently 
measuring data below the NAAQS, but that may have issues maintaining 
that air quality, rather than only former nonattainment areas which are 
in maintenance status.\21\ Therefore, we focused our review on 
SO2 monitoring data and emission trends to evaluate the 
State's conclusion that Utah will not interfere with maintenance of the 
2010 SO2 NAAQS in downwind states. This evaluation builds on 
the analysis regarding significant contribution to nonattainment (prong 
1). Specifically, the low monitored ambient concentrations of 
SO2 in Utah and neighboring states shown in Table 3, and the 
large distances between cross-state SO2 sources shown in 
Tables 4 and 5, do not indicate any potential inability to maintain the 
SO2 NAAQS that could be attributed in part to sources in 
Utah.
---------------------------------------------------------------------------

    \21\ The maintenance plan requirements for areas redesignated 
from nonattainment to attainment for a NAAQS can be found in CAA 
section 175A.
---------------------------------------------------------------------------

    Table 6, below, shows emission trends for Utah and neighboring 
states.\22\
---------------------------------------------------------------------------

    \22\ This emissions trends information was derived from the 
EPA's web page https://www.epa.gov/air-emissions-inventories/air-pollutant-emissions-trends-data.

                                          Table 6--SO2 Emission Trends
----------------------------------------------------------------------------------------------------------------
                                                                                                  SO2 reduction,
                                                                                                     2000-2016
              State                    2000            2005            2010            2016          (percent)
 
----------------------------------------------------------------------------------------------------------------
Arizona.........................         118,528          90,577          73,075          38,089              68
Colorado........................         115,122          80,468          60,459          20,626              82
Idaho...........................          34,525          35,451          14,774          10,051              70
Nevada..........................          58,849          68,790          17,043           8,028              86
New Mexico......................         164,631          47,671          23,651          15,529              90
Utah............................          58,040          52,998          29,776          15,226              73
Wyoming.........................         141,439         122,453          91,022          57,313              59
----------------------------------------------------------------------------------------------------------------

    As shown in Table 6, the statewide SO2 emissions from 
Utah and neighboring states have decreased substantially over time, per 
our review of the EPA's emissions trends data. This trend of decreasing 
SO2 emissions does not by itself demonstrate that areas in 
Utah and neighboring states will maintain the 2010 SO2 
NAAQS. However, as a piece of this weight of evidence analysis for 
prong 2, it provides further indication (when considered alongside low 
monitor values in neighboring states and large distances between 
SO2 emissions sources) that maintenance issues are unlikely. 
The geographic scope and large relative size of these reductions 
strongly suggest that they are not transient effects from reversible 
causes, and thus there is low likelihood that a strong upward trend in 
emissions will occur that might cause areas presently in attainment to 
violate the NAAQS in the future.
    In conclusion, for interstate transport prong 2, we reviewed 
additional information about emission trends, as well as the technical 
information considered for interstate transport prong 1. We propose to 
find that the combination of low ambient concentrations of 
SO2 in Utah and neighboring states, the large distances 
between cross-state SO2 sources, and the downward trend in 
SO2 emissions from Utah and neighboring states, show no 
interference with maintenance of the 2010 SO2 NAAQS from 
Utah. Accordingly, we propose to approve Utah's June 2, 2013 and 
supplemental May 8, 2018 SO2 submissions with respect to the 
prong 2 requirement.

C. Evaluation for the 2012 Annual PM2.5 NAAQS

1. EPA's General Approach To Evaluating the 2012 PM2.5 NAAQS
    The EPA has developed a consistent framework for addressing 
interstate transport with respect to the PM2.5 NAAQS. This 
framework includes the following four steps: (1) Identify downwind 
areas that are expected to have problems attaining or maintaining the 
NAAQS; (2) Identify which upwind states contribute to these air quality 
problems in amounts sufficient to warrant further review and analysis; 
(3) Identify any emissions reductions necessary to prevent an 
identified upwind state from significantly contributing to downwind 
nonattainment or interfering with downwind maintenance of the NAAQS; 
and (4) Adopt permanent and enforceable measures needed to achieve 
those emissions reductions.
    To help states identify the receptors expected to have problems 
attaining or maintaining the 2012 annual PM2.5 NAAQS, the 
EPA released a memorandum titled, ``Information on the Interstate 
Transport `Good Neighbor' Provision for the 2012 Fine Particulate 
Matter National Ambient Air Quality Standards under Clean Air Act 
Section 110(a)(2)(D)(i)(I)'' on March 17, 2016 (hereon ``2016 
Memo'').\23\ The 2016 Memo provides projected future year annual 
PM2.5 design values for monitors throughout the country 
based on quality-assured and certified ambient monitoring data and 
recent air quality modeling and explains the methodology used to 
develop these projected design values. The 2016 Memo also provides 
recommendations on how states can use the projected values to determine 
which monitors should be further evaluated as potential receptors under 
step 1 of the interstate transport framework described above, so that 
states can determine whether their emissions significantly contribute 
to nonattainment or interfere with maintenance of the 2012 annual 
PM2.5 NAAQS at these monitoring sites.
---------------------------------------------------------------------------

    \23\ This memorandum is available in the docket for this action 
and at https://www.epa.gov/sites/production/files/2016-08/documents/good-neighbor-memo_implementation.pdf.
---------------------------------------------------------------------------

    To develop the projected values presented in the 2016 Memo, the EPA 
used the results of nationwide photochemical air quality modeling that 
it recently performed to support two ozone NAAQS-related rulemakings. 
We performed base year modeling for 2011 and future year modeling for 
2017 to support the Cross-State Air Pollution Rule (CSAPR) Update for 
the 2008 Ozone NAAQS. See 81 FR 74504 (October 26, 2016). We also 
performed future year modeling for 2025 to support the Regulatory 
Impact Assessment of the final 2015 Ozone NAAQS.\24\ The outputs from 
these model runs included hourly concentrations of PM2.5 
that the EPA used in conjunction with measured data to project annual 
average PM2.5 design values for 2017 and 2025.
---------------------------------------------------------------------------

    \24\ See 2015 ozone NAAQS RIA at: http://www3.epa.gov/ozonepollution/pdfs/20151001ria.pdf.

---------------------------------------------------------------------------

[[Page 28782]]

    Areas that were designated as Moderate PM2.5 
nonattainment areas for the 2012 annual PM2.5 NAAQS in 2014 
must attain the NAAQS by December 31, 2021, or as expeditiously as 
practicable. Since modeling results are only available for 2017 and 
2025, the 2016 Memo explains that one way to assess potential receptors 
for 2021 \25\ is to assume that receptors projected to have average 
and/or maximum design values above the NAAQS in both 2017 and 2025 are 
also likely to be either nonattainment or maintenance receptors in 
2021. Similarly, the EPA stated that it may be reasonable to assume 
that receptors that are projected to attain the NAAQS in both 2017 and 
2025 are also likely to be attainment receptors in 2021. Where a 
potential receptor is projected to be nonattainment or maintenance in 
2017, but projected to be attainment in 2025, further analysis of the 
emissions and modeling may be needed to make a further judgement 
regarding the receptor status in 2021.\26\
---------------------------------------------------------------------------

    \25\ Assessing downwind PM2.5 air quality problems 
based on estimates of air quality concentrations in a future year 
aligned with the relevant attainment deadline is consistent with the 
instructions from the United States Court of Appeals for the 
District of Columbia Circuit (D.C. Circuit) in North Carolina v. 
EPA, 531 F.3d 896, 911-12 (D.C. Cir. 2008), that upwind emission 
reductions should be harmonized, to the extent possible, with the 
attainment deadlines for downwind areas.
    \26\ The EPA notes that the modeling used to inform the 2016 
Memo did not project any potential nonattainment or maintenance 
receptors in 2025 that were not also projected as potential 
nonattainment or maintenance receptors in 2017.
---------------------------------------------------------------------------

    Based on this approach, the EPA identified nineteen potential 
nonattainment and/or maintenance receptors.\27\ Seventeen of these are 
located in California. One of the potential maintenance-only receptors 
is located in Shoshone County, Idaho, and the other potential 
maintenance-only receptor is located in Allegheny County, Pennsylvania.
---------------------------------------------------------------------------

    \27\ As the EPA explained in the proposed action, titled ``Air 
Plan Approval; AL, FL, GA, KY, MS, NC, SC, TN; Interstate Transport 
for the 2012 PM2.5 NAAQS,'' 83 FR 39387 (Aug. 9, 2018), 
the 2016 Memo noted that because of data quality problems, 
nonattainment and maintenance projections were not conducted for 
monitors in all or portions of Florida, Illinois, Idaho (outside of 
Shoshone County), Tennessee and Kentucky. The EPA noted, however, 
that data quality problems have subsequently been resolved for all 
of the aforementioned areas. These areas have current design values 
below the 2012 PM2.5 NAAQS and are expected to continue 
to maintain the NAAQS (See EPA Region 4 Annual PM2.5 
Trends Analysis TSD, in the docket for this action) due to downward 
emission trends for nitrogen oxides (NOx) and SO2 and 
therefore were not considered potential receptors for the purpose of 
interstate transport for the 2012 PM2.5 NAAQS. The EPA 
finalized approved of the action on September 25, 2018 (83 FR 
48387).
---------------------------------------------------------------------------

    After identifying potential receptors, the next step is to identify 
whether upwind states contribute to air pollution at each of the 
identified receptors in other states. In the 2016 Memo, the EPA did not 
calculate the portion of any downwind state's predicted 
PM2.5 concentrations that would result from emissions from 
individual states. Accordingly, the EPA will evaluate Utah's prong 1 
and 2 submissions using a weight of evidence analysis. This analysis is 
based on a review of the State's submission and other available 
information, including air quality trends; topographical, geographical, 
and meteorological information; local emissions in downwind states and 
emissions from the upwind state; and contribution modeling from prior 
interstate transport analyses. While none of these factors is by itself 
dispositive, together they may be used in weight of evidence analyses 
to determine whether the emissions from Utah will significantly 
contribute to nonattainment or interfere with maintenance of the 2012 
annual PM2.5 NAAQS at the 19 potential nonattainment and/or 
maintenance receptors identified in the 2016 Memo.
2. State's Submission
    Utah conducted a weight of evidence analysis to examine whether 
PM2.5 emissions from Utah adversely affect attainment or 
maintenance of the 2012 PM2.5 NAAQS in downwind states. The 
State's analysis primarily focused on potential contribution to the 
West Silver Valley, Idaho 2012 PM2.5 nonattainment area,\28\ 
which is also the location of the Shoshone County, Idaho potential 
maintenance-only receptor identified in the 2016 Memo and the only area 
in a state bordering Utah that contained a nonattainment or maintenance 
receptor. Utah considered the distance from the State to West Silver 
Valley, as well as meteorological information and PM2.5 
speciation data, and on this basis concluded that the State will not 
contribute significantly to nonattainment or interfere with maintenance 
of the 2012 PM2.5 NAAQS in Idaho or any other state.
---------------------------------------------------------------------------

    \28\ https://www3.epa.gov/airquality/greenbook/kbca.html#PM-2.5.2012.West_Silver_Valley.
---------------------------------------------------------------------------

    The EPA notes that, because Utah's analysis focused on designated 
nonattainment areas, it does not independently address whether the SIP 
contains adequate provisions prohibiting emissions that will interfere 
with maintenance of the 2012 PM2.5 NAAQS in any other state. 
In remanding the Clean Air Interstate Rule (CAIR) to the EPA in North 
Carolina v. EPA, the D.C. Circuit explained that the regulating 
authority must give the ``interfere with maintenance'' clause of 
section 110(a)(2)(D)(i)(I) ``independent significance'' by evaluating 
the impact of upwind state emissions on downwind areas that, while 
currently in attainment, are at risk of future nonattainment, 
considering historic variability.\29\ While Utah's submittal pre-dates 
the 2016 Memo, which provided the states with information about 
potential maintenance-only receptors, Utah was still required to 
evaluate the potential impact of its emissions on areas that are 
currently measuring data below the NAAQS, but that may have issues 
maintaining that air quality, and the State did not do so. The EPA also 
notes that while Utah elected to address areas in neighboring states 
designated as nonattainment for the 2012 PM2.5 NAAQS, the 
State did not also address such areas in non-neighboring states, such 
as California, and should have done so because directly emitted 
PM2.5 and PM2.5 precursors can have long-ranging 
impacts.
---------------------------------------------------------------------------

    \29\ 531 F.3d 896, 910-11 (D.C. Cir. 2008) (holding that the EPA 
must give ``independent significance'' to each prong of CAA section 
110(a)(2)(D)(i)(I)).
---------------------------------------------------------------------------

    When, as here, the EPA determines that a state's SIP has not 
addressed all of the statutory requirements or provided a technical 
analysis to justify its conclusion regarding the state's impact on 
downwind air quality problems, the EPA identifies those deficiencies in 
acting upon the state's SIP submission. However, if the EPA has 
supplemental analysis available that nonetheless supported a state's 
conclusion despite these deficiencies in the state's SIP submission, 
the EPA can nonetheless propose to approve the state's SIP submission. 
See 82 FR 9142, 9149 (Feb. 3, 2017).
3. EPA's Analysis
    The EPA reviewed the information in Utah's submittal, as well as 
the 2016 Memo and additional information for our evaluation, and we 
propose to come to the same conclusion as the State, including (based 
on our supplemental information) Utah's conclusion that emissions from 
the State will not interfere with maintenance in downwind states. The 
EPA therefore proposes to approve the December 22, 2015 submission with 
respect to both the prong 1 and 2 requirements for the 2012 
PM2.5 NAAQS. In our evaluation, we identified potential 
downwind nonattainment and maintenance receptors using the modeling 
results presented in the 2016 Memo. We then

[[Page 28783]]

evaluated these receptors to determine whether Utah emissions could 
significantly contribute to nonattainment or interfere with maintenance 
at them. Below, we provide an overview of our analysis. A more detailed 
evaluation of how the SIP revision meets the requirements of CAA 
section 110(a)(2)(D)(i)(I) may be found in our 2012 PM2.5 
technical support document (TSD) in the docket for this action.
    Our prong 1 analysis focused on the 17 California receptors, which 
include the only nonattainment receptors modeled in the 2016 Memo. As 
shown in Table 1 of the 2016 Memo, 12 of the 17 California receptors 
are projected as nonattainment in both 2017 and 2025, while the 
remaining 5 receptors are projected as maintenance in either 2017 or 
2025. Because all of the 17 California receptors are located in either 
the San Joaquin Valley or South Coast 2012 PM2.5 
nonattainment area, we have elected to analyze all of the California 
receptors together rather than separate the California nonattainment 
and maintenance receptor analyses. Our analysis of these receptors 
showed that elevated PM2.5 levels in California are driven 
primarily by local emissions.\30\ Additionally, Utah's southwestern 
border is more than 290 miles to the east and downwind of the 
California receptors, with intervening mountainous topography which 
tends to impede interstate pollution transport. Finally, as shown in 
Table 7, below, monitoring data from Interagency Monitoring of 
Protected Visual Environment (IMPROVE) monitors tend to show that the 
air in remote areas between Utah and the California nonattainment and 
maintenance receptors is well below the level of the 2012 
PM2.5 NAAQS.\31\ All of these factors indicate that 
emissions from Utah are not likely to reach California in amounts that 
could impact the air quality at the California nonattainment and 
maintenance receptors. Thus, the EPA is proposing to find that Utah 
emissions will not significantly contribute to nonattainment or 
interfere with maintenance of the 2012 PM2.5 NAAQS at any 
California projected receptor.
---------------------------------------------------------------------------

    \30\ See ``California: Imperial County, Los Angeles-South Coast 
Air Basin, Plumas County, San Joaquin Valley Area Designations for 
the 2012 Primary Annual PM2.5 National Ambient Air 
Quality Standard Technical Support Document'' in the docket for this 
action.
    \31\ The IMPROVE program includes a long-term monitoring program 
to establish the current visibility conditions, track changes in 
visibility and determine causal mechanism for the visibility 
impairment in the National Parks and Wilderness Areas (http://vista.cira.colostate.edu/improve/). These monitors are not required 
to meet the same standards as regulatory monitors used by the EPA 
and states to determine compliance with the NAAQS.

 Table 7--PM2.5 Average Annual Concentrations at Remote IMPROVE Monitors
                                  \32\
------------------------------------------------------------------------
                                                             2015-2017
                                                           PM2.5 average
                                                              annual
           Site No.                      State            concentrations
                                                             ([micro]g/
                                                               m\3\)
 
------------------------------------------------------------------------
040159000....................  Arizona..................            2.75
060270002....................  California...............            3.63
060199000....................  California...............            4.06
060519000....................  California...............            2.82
060719002....................  California...............            3.63
160230101....................  Idaho....................            3.23
160370002....................  Idaho....................            3.99
320079000....................  Nevada...................            2.98
320330101....................  Nevada...................            2.25
490530130....................  Utah.....................            2.74
------------------------------------------------------------------------

    For  the EPA's prong 2 analysis, we reviewed potential impacts from 
Utah emissions at the two projected maintenance-only receptors outside 
of California identified in the 2016 Memo. With regard to the Shoshone 
County, Idaho receptor, our analysis showed that elevated 
PM2.5 levels in the area are driven primarily by local 
emissions from wood burning in the wintertime, specifically when the 
West Silver Valley experiences the combination of cold surface 
temperatures, low wind speeds, and constrained vertical mixing.\33\ The 
deep, narrow mountain valley magnifies this effect relative to other 
nearby areas. The combination of these meteorological effects and the 
mountainous terrain confine the geographical area that could contribute 
emissions to elevated wintertime PM2.5 concentrations at the 
Shoshone County receptor.\34\ Utah's prong 1 analysis noted that 
speciation data in the Utah 2006 PM2.5 nonattainment areas 
\35\ indicate that ammonium nitrate drives high PM2.5 levels 
in north-central Utah, which contrasts with carbon-driven speciation 
data at the Shoshone County receptor during the winter and indicates 
emissions originating in Utah are not contributing to elevated 
PM2.5 at the Shoshone County receptor. Additionally, Utah's 
nearest border is approximately 400 miles to the southeast and 
generally downwind of this receptor. Finally, the IMPROVE monitoring 
data in Table 7 tend to show that the air in remote areas in Idaho 
between Utah and the Shoshone County receptor is well below the level 
of the 2012 PM2.5 NAAQS. This provides further indication 
that elevated PM2.5 at the Shoshone County receptor is 
primarily driven by local emissions. All of these factors indicate that 
emissions from Utah will not interfere with maintenance of the 2012 
PM2.5 NAAQS at the projected Shoshone County maintenance 
receptor.
---------------------------------------------------------------------------

    \32\ Id.
    \33\ See ``Idaho: West Silver Valley Nonattainment Area--2012 
Primary Annual PM2.5 National Ambient Air Quality 
Standard Technical Support Document'' in the docket for this action.
    \34\ Id.at 39.
    \35\ https://www3.epa.gov/airquality/greenbook/rbtc.html.
---------------------------------------------------------------------------

    With regard to the Allegheny County, Pennsylvania potential 
maintenance receptor, our analysis included review of previous modeling 
data conducted for the EPA's 2011 CSAPR, which addressed the 1997 and 
2006 PM2.5 NAAQS.\36\ For the 2011 CSAPR, the EPA modeled 
contribution from states in the eastern U.S. to air quality monitors 
also located in the eastern

[[Page 28784]]

U.S.\37\ Therefore, the 2011 CSAPR modeling did not project downwind 
contribution of emissions from Utah, but projected contributions from 
states east of Utah, including Kansas and Nebraska. The CSAPR modeling 
indicated that Kansas and Nebraska, states located much closer to the 
Allegheny County receptor and with higher PM2.5 precursor 
emissions than Utah,\38\ were modeled to be below 1% (the contribution 
level at which eastern states were considered ``linked'' to downwind 
receptors in the CSAPR and CSAPR Update rulemakings) of the 1997 annual 
and 2006 24-hr PM2.5 NAAQS at the Allegheny County receptor. 
These factors, in addition to the very large distance (1,525 miles) 
from the Allegheny County receptor to the Utah border, indicate that 
emissions from Utah will not interfere with maintenance of the 2012 
PM2.5 NAAQS at the projected Allegheny County receptor.
---------------------------------------------------------------------------

    \36\ See Table V.D-1 in the EPA's CSAPR (August 8, 2011), at 76 
FR 48240.
    \37\ In these rules, ``Eastern'' states refer to all contiguous 
states east of the Rocky Mountains, specifically not including: 
Montana, Wyoming, Colorado and New Mexico.
    \38\ See Tables 7-1 and 7-2 in ``Emissions Inventory Final Rule 
Technical Support Document (TSD)'' for CSAPR, June 28, 2011, 
Document number EPA-HQ-OAR-2009-0491-4522 in www.regulations.gov.
---------------------------------------------------------------------------

    Based on these analyses, the EPA is proposing to determine that 
Utah emissions will not contribute significantly to nonattainment or 
interfere with maintenance of the 2012 PM2.5 NAAQS in any 
other state, and we therefore propose to approve the December 22, 2015 
submittal.

III. Proposed Action

    Based on our review of Utah's January 31, 2013, June 2, 2013, 
December 22, 2015 and May 8, 2018 infrastructure submissions, and our 
analysis of additional relevant information, we propose to determine 
that emissions from Utah will not significantly contribute to 
nonattainment, or interfere with maintenance, of the 2010 
NO2, 2010 SO2, and 2012 PM2.5 NAAQS in 
any other state. Accordingly, we propose to approve the January 31, 
2013, June 2, 2013, December 22, 2015 and May 8, 2018 Utah SIP 
submissions as satisfying the requirements of CAA section 
110(a)(2)(D)(i)(I) for these NAAQS. The EPA is soliciting public 
comments on this proposed action and will consider public comments 
received during the comment period.

IV. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP 
submission that complies with the provisions of the Act and applicable 
federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in 
reviewing SIP submissions, the EPA's role is to approve state choices, 
provided that they meet the criteria of the CAA. Accordingly, this 
action merely proposes to approve state law as meeting federal 
requirements and does not impose additional requirements beyond those 
imposed by state law. For that reason, this action:
     Is not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Orders 
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 
2011);
     Is not an Executive Order 13771 (82 FR 9339, February 2, 
2017) regulatory action because SIP approvals are exempted under 
Executive Order 12866;
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the CAA; and
     Does not provide the EPA with the discretionary authority 
to address, as appropriate, disproportionate human health or 
environmental effects, using practicable and legally permissible 
methods, under Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, the SIP is not approved to apply on any Indian 
reservation land or in any other area where the EPA or an Indian tribe 
has demonstrated that a tribe has jurisdiction. In those areas of 
Indian country, the proposed rule does not have tribal implications and 
will not impose substantial direct costs on tribal governments or 
preempt tribal law as specified by Executive Order 13175 (65 FR 67249, 
November 9, 2000).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Intergovernmental relations, Nitrogen dioxide, Ozone, 
Particulate matter, Reporting and recordkeeping requirements, Sulfur 
dioxide, Volatile organic compounds.

    Authority:  42 U.S.C. 7401 et seq.

    Dated: June 10, 2019.
Debra Thomas,
Acting Regional Administrator, EPA Region 8.
[FR Doc. 2019-12948 Filed 6-19-19; 8:45 am]
 BILLING CODE 6560-50-P


